About 5-10 minutes in the tub. If I have sunburn, then I soak for longer to let the water really take the heat out of my skin. But I haven't had a bath in a long time, I'm a shower type of person.
In 13 years I've had snakes, I think I've soaked or given some type of bath on 3 occasions cause of a super bad shed or the snake was so covered in feces, a bath was the only way to get the stench off. And when I moved all my snakes crapped their bags. So they all got a bath then. It was gross.